A storage system provided with a function for detecting a write completion is known for instance. The storage system is provided with a plurality of storage apparatuses and a control module coupled with the plurality of storage apparatuses. The control module is provided with at least one processor module that transmits a write packet, at least one storage resource, and at least one transfer control module coupled with the processor module and the storage resource. The transfer control module is provided with a receiver and a transmitter. The receiver receives a write packet from the processor module, and transmits a write packet provided with the following (1-A) to (1-D) on the basis of the write packet received from the processor,
(1-A) a write code that is a code representing a write;
(1-B) a specific code;
(1-C) write target data; and
(1-D) destination information indicating a storage resource of a write destination.
When the transmitter receives a write packet and the received write packet includes the specific code, the transmitter writes the write target data in the received write packet to the storage resource indicated by the destination information in the packet, creates a response packet that is a packet corresponding to a response indicating a completion of a write, and transmits the created response packet (for instance, PTL 1).